Process for crimping thermoplastic filamentary material



Dec. 26, 1967 WNICKI ETAL 3,359,609

PROCESS FOR CRIMPING THERMOPLASTIC FILAMENTARY MATERIAL- Filed Sept. 14,1964 5 Sheets-Sheet 1 gym 2 Attorney PROCESS FOR CRIMPING THERMOPLASTICFILAMENTARY MATERIAL 5 Sheets-Sheet 2 Filed Sept. 14, 1964 A ttorneys26, 1967 K. lWNlCKI ETAL 3,359,609

PROCESS FOR CRIMPING THERMOPLASTIC FILAMENTARY MATERIAL United StatesPatent 3,359,609 PROCESS FOR CRlMPING THERMOPLASTIC FILAMENTARY MATERIALKurt Iwnicki, Ponthir, and James Frederick Thomas, Newport, England,assignors to British Nylon Spinners Limited, Pontypool, Monmouthshire,England Filed Sept. 14, 1964, Ser. No. 396,190 Claims priority, aplication Great Britain, Sept. 26, 1963, 37,848/ 63 6 Claims. (Cl.28-72) ABSTRACT OF THE DISCLOSURE Method and apparatus for crimping andsetting filaments wherein the filaments are forced into a stufier-boxcrimping chamber from which they pass tangentially into an annularsetting chamber in the form of helical coils. The setting chamber isformed between inner and outer cylindrical members one of which isrotatable for the purpose of maintaining crimping back pressure.

The invention concerns a process for crimping thermoplastic filamentarymaterial, such as yarns and tows of nylon continuous filaments.

even if no heat is needed to be applied.

One way in which such crimping and crimp-setting may be achieved is byemploying a crimping chamber and a 7 distinct but adjacent settingchamber. The known setting chambers are straight and directly in linewith the length direction of the crimping chambers.

The length of a setting chamber is selected having in mind the length oftime which it is required that the crimped yarn or tow shall besubmitted to conditioning or heat-setting, in order that the crimp shallbe completely and uniformly set. The greater the throughput, normallythe longer the setting chamber is required to be; but considerations ofspace, and of the behaviour of the mass of crimped yarn or tow in a verylong column of compacted filamentary material, serve in fact to limitthe straight line length of a setting chamber, in any given process.

One way in which such a limitation on the length of a setting chambercan be avoided is by the use of a rotatable circular setting chamber, apart or parts of which are adapted to provide motion to the tow or yarnin the direction of rotation.

Whereas we are aware that such rotatable, circular chambers havepreviously been proposed for one purpose or another in connection withcompression crimping, it appears that only about 180 of arc, at themost, have been employed for setting purposes. Thus, whilst some littleimprovement over straight setting chambers in respect of spaceconservation may have been achieved by such rotatable, circularchambers, no great headway has ment in the uniformity of setting.

In two co-pending patent applications filed on even 7 date hereto, wehave described a basically new concept of treatment for filamentarymaterial, involving the use of a rotatable treatment chamber, e.g. forheat-setting yarn or tOW.

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According to the first such application, a process for treatingfilamentary material comprises the steps of positively forwarding saidmaterial continuously and at least substantially tangentially to one endof a treatment zone constituted by an annular space bounded by an outerand an inner cylindrical member, at least one said member beingrotatable about its axis in a direction such that it is travelling inthe same direction as the forwarded filamentary material at the point ofinitial contact therewith, of advancing said material in the axialdirection of said members towards the other end of said treatment zonein the form of contiguous helical coils between said members, and ofremoving said material from said other end of said treatment zone.

According to the second such application, apparatus for treating andadvancing filamentary material comprises an inner cylindrical member andan outer cylindrical member, said members defining between them anannular space and at least one such member being adapted for rotationabout its axis, and means closing one end of said annular space andproviding an internal filamentary material-contacting cam surface ofhelical nature.

It is an object of the present invention to make use of the principle ofafter-treatment which is disclosed in the above mentioned two co-pendingapplications, and to apply it to overcoming the disadvantages,particularly of space, inherent in known compression crimping processes.

According to the invention, a process for crimping and treatingthermoplastic filamentary material comprises forcing a unit of saidmaterial continuously into a confined space in which the material isbuckled to assume a crimped configuration and is accumulated incompacted condition, forwarding the compacted crimped filamentarymaterial from said space at least substantially tangentially into oneend of an annular treating zone by the pressure exerted upon it in saidspace, in which zone the crimped filamentary material, still incompacted condition, is advanced, substantially normally to thedirection in which it was forwarded, in a plurality of contiguoushelical coils along the annular zone, and withdrawing the crimpedfilamentary material in unitary form from the last of said helicalcoils.

Thus, by the process of the invention, the compacted crimped filamentarymaterial is accumulated in coils for treating, e.g. crimp-setting byheat treatment in the treating zone, and the direction of progression ofsaid material is changed through a right angle. When the crimpedfilamentary material is finally withdrawn from the last of theaccumulated coils, the direction of withdrawal can be parallel to thatof the progression of coils along the heating zone, or any directionthereabouts up to the perpendicular thereto.

The unit of thermoplastic filamentary material, which may, for instance,be a plurality of heavy denier nylon continuous filament yarns, may beforced into the confined space by nip rolls as in a standard stuifer-boxcrimper.

The front and back walls of the stutter-box chamber are shaped to enablethe compacted crimped filamentary material to be forced directly intoone end of the annular treating zone, with no gaps big enough forfilaments to get trapped in.

The direction and point of feed into the annular treating zone, whichzone is preferably contained in apparatus of the kind described in ourabove mentioned second 00- pending application, are preferablydownwardly and to one side of the axis of said zone, respectively, i.e.at least substantially tangentially to said annular heating zone.

Heating of the thermoplastic filamentary material within the zone, ifrequired, can be by any of the usual means, such as electricalresistance heaters, as described in the aforementioned co-pendingapplications.

The effect of the coiled accumulation of filamentary material in theannular treating zone is to enable very prolonged and throughconditioning, e.g. heat-setting, of the crimp to take place without, forinstance, employing dangerously high temperatures.

The annular treating zone may be mounted simply with its inner and/ orouter cylindrical members rotatable by the action of the forwarded,compacted crimped filamentary material, in which case the rotatablemember or members has to be braked by an amount appropriate for theinitiation of crimping back pressure; or, alternatively, such members ormembers may be so driven, in the direction of forwarding of material,that the said crimping back pressure is initiated and regulated.

A yieldable closure member, such as the bell-shaped plunger referred toin the aforementioned co-pending applications, may usefully be employedfor retaining a given light pressure on the coils of compacted crimpedmaterial in the treating zone; and such yieldable member may also serveas a means for ensuring that a unit of material, e.g. a yarn or acoherent plurality of yarns, is uniformly withdrawn from the compactedmass in the last coil, without snarls, knots or other tangles beingallowed to remain, and as a means for sensing continuously the amount ofmaterial within the treating zone.

As stated above, the apparatus incorporating the treating zone ispreferably that described and claimed in our aforementioned secondco-pending application.

Conveniently, the overall control of the running of the present processis in accordance with a process whereby the amount of filamentarymaterial within the heatsetting zone is sensed by the yieldable closuremember, and the movement of such member is used to control, preferablyelectrically, a ten-sioning device to apply a variable tension to thefilamentary material withdrawn from the zone, to keep the amount in thezone substantially constant.

Finally, thefilamentary material may be cooled prior to, or subsequentto, its withdrawal from the treating zone, and in any event prior towind-up, in order that the crimp shall not be removed owing to thematerial still being, for instance, in a plastic condition at the time,when the tension of winding-up is applied to it.

The process of the invention has been used for crimping together threeends (i.e. singles yarns) of multifilament yarn of polyhexamethyleneadipamide (nylon 66), each of some 1000 denier, at speeds up to at least3000 feet per minute.

The invention will now be described with reference tothe accompanyingdrawings, in which FIGURE 1 is a diagram of a combined drawing andcrimping lay-out in which the invention is employed;

FIGURE 2 is a longitudinal partly sectional view, through X-X of FIGURE3, of crimping and advancing apparatus embodying the principle of theinvention;

FIGURE 3 is a transverse sectional view, through YY of FIGURE 2, of thesaid crimping and advancing apparatus;

FIGURE 4 is a plan view of a flange-like member employed in the saidcrimping and advancing apparatus;

FIGURE 5 is a side view on A of FIGURE 4;

FIGURE 6 is a side view on B of FIGURE 4;

FIGURE 7 is a side view on C of FIGURE 4.

The lay-out depicted in FIGURE 1 comprises the withdrawal of undrawnyarn Y from square-ended package -1 wound on cylindrical former 3 bymeans of driven nip rolls 9.'The yarn Y balloons on take-off and isdrawn through balloon guide 5, on the axis of former 3, and

thence through thread guide 7.

The undrawn yarn is then forwarded under tension to the drawing stagecomprising feed roll 11, with its separator roll 13, and draw roll 17,with its separator roll 19. Between the feed and draw rolls the yarn iswrapped around snubbing pin to create the point of draw. The

pin may be heated by internal electric resistance means (not shown).

On departure from the draw roll 17 the yarn is fully drawn, and it isnow directly submitted to crimping in the compression crimping stage.

The compression crimping apparatus comprises feed roll 21, Whoseperiphery is directly driven by that of crimper roll 23, and crimperrolls 23 and 25. The drawn yarn is passed under feed roll 21, throughthe nip between it and crimper roll 23, and thence down through the nipof crimper rolls 2'3, 25 into the crimping chamber generally indicatedat 27.

From the crimping chamber, the crimped yarn passes directly into theannular treating chamber generally indicated at 29.

Both said crimping apparatus and said annular treating chamber will bemore specifically described with reference to FIGURES 2 and 3; but inFIGURE 1 it is shown that a rotary part of said annular treating chamberincludes driving wharl 35 fixed to a shaft rotatable in axially spacedbearings 33. Slida'ole axially of said shaft is spindle 37 ofbell-shaped plunger 31, the latter serving as closure member for thedischarge end of the annular treating chamber 29.

The yarn on withdrawal from the annular treating chamber 29 is crimped,and is now designated Y Withdrawal is effected by rotation of wind-uproll 57 carrying package 55 by the surface drive of said package fromthe periphery of drive roll 53. Crimped yarn Y is passed through threadguide 43 on the axis of the annular treating chamber; and thence aroundtensioning bollards 45 for imparting a low tension to the yarn so thatit is in even condition when passed around the periphery of magneticparticle yarn brake 47. Finally, the yarn is passed over pin 49 andthence through reciprocating thread-guide 51 for traversing the yarn onto the wind-up package 55.

The regulation of the amount of yarn within the annular treating chamber29 is performed by the function of the bell-shaped plunger 31 and theyarn brake 47. The plunger 31 is spring-loaded and hence its axialposition with respect to the chamber 29 will give an indication of theamount of yarn compacted within the chamber. Movement of the plunger 31and its spindle 37 is arranged to be transmitted, via the lever 39 and acam fixedly mounted to the pivot thereof, to roller 41 on the spring-armof a micro-switch.

The micro-switch is contained in an electrical circuit fed from thealternating current mains via two-tap transformer 59. Depending onwhether the switch is made or broken, alternating current at either ahigh or a low voltage is supplied from the thus selected tapping of thetransformer to rectifier circuit 61. The direct current output of saidrectifier, at either the high or the low voltage, is fed to magneticparticle yarn brake 47, whereby more or less braking effect is impartedto the crimped yarn. The more the yarn is braked, the higher will be thetension in the yarn between the brake and the windup; and, as thecrimped yarn is extensible, the higher the tension the less amount, inweight, of yarn will be wound in unit time. Hence, the amount of yarnwithdrawn from the annular treating chamber in unit time can becontrolled by these means.

The crimping and advancing apparatus shown in FIG- URES 2 and 3 embodiesthe principle of the invention wherein yarn or the like is treated in anannular chamber whilst being advanced in contiguous coils axially ofthat chamber.

In the embodiment depicted in these two figures, yarn Y is fed by feedroll 21 into the nip of crimper rolls 23, 25, as already described withrespect to FIGURE 1.

The crimping chamber 27 of the stutter-box type of compression crimpercomprises back wall 70, front wall 77 and side walls 67, 69. These wallsare shaped at their lower ends to fit closely against the outercylindrical shell 71 of annular treating and advancing chamber 29.

The inlet end of the chamber 29 is closed by flangelike closure member63 having an inwardly-facing helical cam surface 79-81, which will bedescribed in greater detail with respect to FIGURES 4-7, in which italone is depicted.

The crimped yarn is forced in a compressed column from the crimpingchamber directly downwardly into the annular treating chamber, aroundwhich it is advanced in contiguous coils 75 of compressed yarn nature.

The annular chamber is formed by the fixed outer cylindrical shell 71and the inner rotatable roller 73. The surface of the roller 73 iscorrugated longitudinally, i.e. in the axial direction.

The discharge end of the annular chamber is provided with a closuremember in the form of bell-shaped plunger 31, around the rim of whichthe crimped yarn Y is withdrawn through guide 43. The plunger 31 islightly held in contact with the furthermost coil of compressed yarn byreason of compressed spring 65 by which its spindle 37 is urged in theleftward direction of FIG- URE 2.

As shown partially in FIGURES 2 and 3, and fully in FIGURES 4-7, theflange-like member 63 has an inwardly-facing helical cam surface 79-81of some 405 in arcuate extent. By such means the first coil ofcompressed yarn is formed and is kept separate from the succeeding coilso as to avoid entanglement of the filaments of the respective coils.This is best understood from a consideration of FIGURE 6; the compressedmass of crimped yarn is forced into the rectangular space bounded by theflange 63 on one side, the end 81 of the helical cam surface on theopposite side, a flat surface 78 cut in the cam surface support and theback wall 70 of the crimping chamber (not shown in FIGURE 6).

As described with reference to FIGURE 1, the rotatable roller 73 of theannular treating chamber is positively driven from wharl 35, and itsshaft is supported in axially spaced bearings 33. The spindle 37 ofplunger 31 is slideable within said shaft against the force of spring65.

If it is desired positively to treat, e.g. to heat-set, the yarn in theannular chamber 29, and not merely to condition it thereon during itsaxial advance, the outer cylindrical shell 71 may have an electricalresistance heater jacket attached exteriorly thereof. Alternatively, orin addition, the interior of roller 73 may be provided with electriccartridge heaters, the electric supply to which can be via slip-rings onthe shaft between bearings 33.

The invention will now be described, by way of example only, by thespecific operating conditions of processes for crimping yarns ofpolyhexamethylene adipamide.

Example I Three ends (single yarns) of drawn 1040 denier/ 68 filamentcontinuous-filament yarn of polyhexamethylene adipamide were withdrawnfrom draw-twist packages by means of rolls as illustrated in FIGURE 2,and a tension of 200 grams was applied to each end by pulling the yarnthrough a tension-imparting device.

The crimping rolls were positively driven at a peripheral speed of 1500feet/minute; and the fluted roller of the annular treating chamber wasrotated at 35 revolutions per minute. Under these conditions, 12 coilsof compressed yarn were maintained within the annular chamber, which washeated to 180 C. 'by means of an electric resistance in an annularjacket surrounding the outer cylindrical shell.

The crimped yarn was withdrawn and wound-up according to the arrangementdepicted in FIGURE 1, the wind-up speed being 1300 feet/minute. Themagnetic particle brake oscillated between a high setting of 300 gramsand a low setting of 100 grams.

The crimped yarn was adequately bulked, having a skein length (15 gramsweight) of 12% inches.

6 Example 11 Three ends (single yarns) of undrawn3600 denier/ 68filament yarn of polyhexamethylene adipamide were withdrawn fromspinning cylinder supply packages, and drawn at a draw ratio of 3.711and crimped according to the arrangement depicted in FIGURE 1. Thecrimping rolls were positively rotated at a peripheral speed of 1500feet/minute; and the fluted roller of the annular treating chamber wasrotated at 42 revolutions per minute. No heat was supplied to the wallsof-the annular treating chamber, the temperature of which rose to 90 C.due to the heat imparted from the yarn.

12 coils of compressed yarn were maintained in the chamber.

The crimped yarn was bulked to an equivalent skein length value to thatof the yarn of Example I, the actual skein length being 15 inches with aweight of 60 grams employed, rather than 15 grams.

Example III The conditions of Example II were the same, except that theperipheral speed of the crimping rolls was 3000 feet/minute, and therotational speed of the roller in the annular treating chamber wasrevolutions per minute.

Example IV The process described in Example II was repeated forequivalent undrawn yarns of Terylene polyester fibre, but in thisinstance the snubbing pin was heated and the yarn was forwarded from thedraw roll to the stuffer-box rolls at a low degree of mechanicalunderfeed, i.e. the feed rolls were rotated at a peripheral speedslightly higher than that of the draw roll.

What we claim is:

1. A process for crimping and treating thermoplastic filamentarymaterial comprising the steps of (a) forcing a unit of said materialcontinuously into a confined space in which the material is buckled toassume a crimped configuration and is accumulated in compactedcondition;

(b) forwarding said compacted crimped filamentary material from saidspace of the pressure exerted upon it in said space;

(c) directing the forward material at least substantially tangentiallyinto one end of an annular treating zone formed by arranging an innercylindrical member within an outer cylindrical member, at least one ofsaid members being rotatable about its axis;

(d) advancing said material axially of said zone in a plurality ofcontiguous helical coils therealong; and

(e) continuously withdrawing the crimped filamentary material in unitaryform from the last of said helical coils.

2. A process according to claim 1, in which said compacted crimpedfilamentary material is advanced along said annular treating zone bycontinuously forming said material into a helical coil as it is directedinto said zone and by rotating the inner cylindrical member definingsaid zone.

3. A process according to claim 2 in which the rotation of the innercylindrical member regulates crimping back pressure in said confinedspace.

4. A process as in claim 3 wherein the inner cylindrical member isrotated at a speed to maintain about 12 coils of the filamentarymaterial in said annular treating zone.

5. A process according to claim 1 and having the further steps of (a)continuously sensing the axial position of the last of said contiguoushelical coils in said annular treating zone; and

(-b) regulating the tension applied by a tensioning device to thecrimped filamentary material withdrawn from said zone in accordance withsaid axial position.

6. A process for crimping and treating undrawn thermoplastic filamentarymaterial comprising the steps of (a) continuously drawing a unit of saidmaterial to orient the molecules thereof;

(b) continuously forwarding said drawn material at a uniform rate tofeed means for a stutter-box crimper;

(c) crimping said drawn material in said crimper;

(d) forwarding said drawn crimped material out of said 'crimper incompacted form by the pressure exerted on it in said crimper;

(e) directing said material at least substantially tangentially into oneend of an annular treating zone;

,(f) advancing said material axially of said zone in a plurality ofcontiguous helical coils therealong whilst 15 the crimp is set; and

(g) continuously withdrawing the material in unitary form from the lastof said helical coils.

References Cited UNITED STATES PATENTS 3,046,633 7/1962 Ohashi et al.281 3,108,352 10/1963 Haigler et al. 3,145,947 8/1964 Stanley. 3,311,9614/1967 Iwnicki et al. 2S72 FOREIGN PATENTS 3,611,633 6/1962 Switzerland.

MERVIN STEIN, Primary Examiner. I. C. WADDEY, Assistant Examiner.

6. A PROCESS FOR CRIMPING AND TREATING UNDRAWN THERMOPLASTIC FILAMENTARYMATERIAL COMPRISING THE STEPS OF (A) CONTINUOUSLY DRAWING A UNIT OF SAIDMATERIAL TO ORIENT THE MOLECULES THEREOF; (B) CONTINUOUSLY FORWARDINGSAID DRAWN MATERIAL AT A UNIFORM RATE TO FEED MEANS FOR A STUFFER-BOXCRIMPER; (C) CRIMPING SAID DRAWN MATERIAL IN SAID CRIMPER; (D)FORWARDING SAID DRAWN CRIMPED MATERIAL OUT OF SAID CRIMPER IN COMPACTEDFORM BY THE PRESSURE EXERTED ON IT IN SAID CRIMPER; (E) DIRECTING SAIDMATERIAL AT LEAST SUBSTNTIALLY TANGENTIALLY INTO ONE END OF AN ANNULARTREATING ZONE; (F) ADVANCING SAID MATERIAL AXIALLY OF SAID ZONE IN APLURALITY OF CONTIGUOUS HELICAL COILS THEREALONG WHILST THE CRIMP ISSET; AND (G) CONTINUOUSLY WITHDRAWING THE MATERIAL IN UNITARY FORM FROMTHE LAST OF SAID HELICAL COILS.